The present invention relates generally to seals for movable windowpanes in automotive vehicles. More particularly, the present invention relates to a frameless window assembly using a magnetic seal and having a movable windowpane capable of having all edges flush with the adjacent vehicle body panel.
In recent years there has been much interest in aerodynamically designed automotive vehicles having windowpanes with all edges substantially flush (hereinafter referred to as "full flush") with the vehicle body. One such system is described in U.S. Application No. 272,566 entitled "Four-Sided Flush Glass Assembly" filed by Keys et al. on Nov. 16, 1988, and which is specifically incorporated herein by reference. Full flush window systems, however, pose unique problems with respect to windowpane movement. For example, since a full flush windowpane is flush with the vehicle body at the beltline, opening of the window requires lateral or transverse inward movement of the windowpane at the beltline prior to its descent into the tracking channel in the vehicle door. Conventional framed automotive windows do not permit such lateral or transverse movement of the windowpane. Although elimination of window framework to allow for such movement would circumvent this problem, it is difficult to achieve a satisfactory window seal in frameless systems using conventional sealing techniques.
For example, automotive windows are conventionally sealed using elastomeric strips which depend primarily upon compression for their sealing force. In frameless window systems, the use of conventional sealing strips generally requires higher compression to form an adequate seal, making it difficult to open and close the windows of the vehicle. Moreover, repeated compression of a sealing strip, particularly one requiring high compressive force for sealing, shortens the effective sealing life of the strip. If less compression of the strip is used to offset these problems, the integrity of the seal between the windowpane and vehicle body is reduced. This leads to increased windowpane flutter, wind noise and air entering the passenger compartment during operation of the vehicle.
One alternative to compression-dependent sealing involves the use of magnetic elements in the sealing arrangement. Conventional magnetic seals such as that proposed in U.S. Pat. No. 4,535,563 to Mesnel, do not, however, offer an adequate solution to the sealing problems encountered in full flush or frameless window systems. For example, in frameless systems the windowpane is sealed directly to the automotive body and opening of the vehicle door requires breaking the seal between the windowpane and the vehicle. If the windowpane is sealed to the body using a conventional magnetic sealing arrangement, opening the vehicle door is difficult since the magnetic seal must be broken at all points simultaneously. In addition, in full flush window systems having lateral or transverse windowpane movement at the beltline, conventional magnetic sealing assemblies offer undue resistance to such movement. The resistance can be so great as to prevent use of a conventional camming mechanism for lateral or transverse windowpane movement.
Thus, it would be desirable to provide a window seal assembly suitable for a full flush or a frameless window system having a satisfactory seal between the window and the automotive body. It would also be desirable to provide a window seal assembly in which the sealing force is not entirely dependent upon the compression of the sealing member. It would further be desirable to provide a satisfactory window seal assembly for a window which is opened and closed by a camming mechanism, in which the sealing member does not offer undue compressive resistance to lateral or transverse movement of the windowpane at the beltline. It would also be desirable to provide a magnetic window seal assembly for a frameless system in which the door can be easily opened with the windowpane in the ascended, i.e. window opening closed, position.